Fig. 2

Effects of anti-high mobility group box 1 (anti-HMGB1) monoclonal antibody (mAb) treatment on lung histology after H1N1 inoculation. a. Photomicrographs of lung tissue samples stained with hematoxylin and eosin on days 3, 5 and 7 after H1N1 inoculation. These are representative of five independent experiments. Control mAb group lung tissue showed aggravating diffuse alveolar and interstitial edema, inflammatory cellular infiltration, hemorrhage and bronchiolitis (upper row). In the anti-HMGB1 mAb group lung tissue, these features were less severe (lower row). Scale bar = 100 μm. b. Lung injury scores. Data represent the mean (± SEM) of five independent experiments; *p <0.05 and **p <0.01 vs control by Mann–Whitney U test. c. Photomicrographs of lung tissue samples stained with granulocyte-differentiating antigen (Gr-1) on day 10 after H1N1 inoculation. These are representative of five independent experiments: (a) H1N1 inoculation, control group; and (b) H1N1 inoculation, anti-HMGB1 mAb group. Arrowheads indicate Gr-1 expressing, positively stained (brown) cells. Scale bar = 100 μm. d. Neutrophil numbers in the bronchoalveolar lavage fluid. Dotted line indicates the normal basal level. Data represent the mean (± SEM) of 10 mice; *p <0.05 and **p <0.01 vs control by Mann–Whitney U test